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Full text of "USPTO Patents Application 09943217"

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What is claimed is: 

1. A catalyst for producing aliphatic polycarbonate, comprising a rare-earth 
coordination compound with the formula: 

MX n Y m 

wherein, M is a rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, 
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tu, Yb, Lu, and a mixture of two or more of the rare earth 
element; X is a carboxylic acid group or sulfonic acid group with Ka values above 10~ 3 ; Y is 
selected from the group consisting of -CI, -NO2 , =0, -OH; n and m is dependency an integer 
from 0 to 3; 

an alkyl metal compound, wherein the metal is zinc, magnesium or aluminum, and the 
alkyl group is selected from the group consisting of CH3-, CH3CH2-, CH3CH2CH2-, 
(CH 2 ) 2 CH-, CH 3 CH 2 CH 2 CH 2 ~, (CH 2 ) 2 CHCH 2 -, and CH 3 CH(CH 3 )CH 2 -; 

a polyol selected from the group consisting of ethylene glycol, diethylene glycol, 
Methylene glycol, 1,2-propanediol, 1,3-propanediol, glycerin and a mixture thereof; and 

a carbonate selected from the group consisting of ethylene carbonate, propylene 
carbonate, cyclohexylene carbonate and a mixture thereof. 

2. The catalyst of claim 1, wherein the carboxylic acid group or sulfonic acid group is 
selected from the group consisting of trifluoroacettic group, trichloroacetic group, 
dichloroacetic group, chloroacetic group, o-chlorobenzoic group, a-tartaric acid group, 
benzene sulfonic acid group, naphthalene sulfonic acid group and a mixture of one or more 
of them. 

3. The catalyst of claim 1, wherein the rare earth metal element is yttrium or 
neodymium. 



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4. The catalyst of claim 1, wherein the carboxylic acid group of the rare earth 
coordination compound is trifluoroacetic group, trichloroacetic group or dichloroacetic 
group. 



5. The catalyst of claim 1, wherein Y is -CI or -OH. 

6. The catalyst of claim 1, wherein the metal alkyl metal is zinc, and alkyl group is 
CH3CH2-, CH 3 CH 2 CH 2 - (CH 2 ) 2 CH- , or CH 3 CH 2 CH 2 CH 2 -. 

7. The catalyst of claim 1, wherein the polyol is 1,2-propylene glycol, or glycerin. 

8. The catalyst of claim 1, wherein said carbonate is propylene carbonate. 

9. A method for preparing the catalyst of claim 1, comprising the steps of: 
(a) sequentially adding 

a polyol selected from the group consisting of ethylene glycol, diethylene 
glycol, triethylene glycol, 1,2-propandiol, 1,3-propandiol, glycerin and a mixture 
thereof; 

a rare-earth coordination compound of the formula MX n Y m , wherein, M is a 
rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, 
Eu, Gd, Tb, Dy, Ho, Er, Tu, Yb, Lu, and a mixture of two or more of the rare 
earth element; X is a carboxylic acid group or sulfonic acid group with Ka values 
above 10" 3 ; Y is selected from the group consisting of -CI, -N0 2 , =0, -OH; n and 
m are independently integers from 0 to 3; 

and an alkyl metal compound, wherein the metal is zinc, magnesium or 
aluminum, and the alkyl group is selected from the group consisting of CH3-, 
CH 3 CH 2 -, CH 3 CH 2 CH 2 -, (CH 2 ) 2 CH-, CH 3 CH 2 CH 2 CH 2 -, (CH 2 ) 2 CHCH 2 -, and 
CH 3 CH(CH 3 )CH 2 -; 



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to the carbonate selected from the group consisting of ethylene carbonate, 
propylene carbonate, cyclohexylene carbonate and a mixture thereof; 

(b) stirring or grinding the mixture thus obtained; 

(c) aging the mixture for 1-24 hours under 0-50 times atmospheric pressure of 
nitrogen, argon, carbon dioxide or under supercritical condition. 

10. The method of claim 9, wherein the carboxylic acid group or sulfonic acid group of 
step (a) is selected from the group consisting of trifluoroacetic group, trichloroacetic group, 
dichloroacetic group, chloroacetic group, o-chlorobenzoicgroup, a-tartaric acid group, 
benzene sulfonic acid group, naphthalene sulfonic acid group and a mixture of one or more 
of them. 

11. The method of claim 9, wherein the mixture in step (c) is aged under the C0 2 
atmosphere. 

12. A method for preparing aliphatic polycarbonate by using the catalyst of claim 1, 
comprising the steps of: 

adding the catalyst of claim 1 and an epoxide into an autoclave; 

filling the autoclave with carbon dioxide and maintaining the pressure between 10-40 
atmospheres; 

allowing copolymerization reaction to proceed at 60-100°C for 5-24 hours; 
adding a HCl/methanol solution, preferably 50% by weight, or an aqueous HC1 
solution, preferably 5% by weight to terminate the reaction, thus obtaining a polycarbonate. 

13. The method of claim 12, wherein the process is carried out in the absence of 
solvent. 



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